Pass gates are electronic components used to either pass a signal between first and second terminals in a first, low-impedance state (e.g., an “on” state), or to isolate the first and second terminals in a second, high-impedance state (e.g., an “off” state). A pass gate can include one or more metal-oxide-semiconductor field-effect transistors (MOSFETs) configured to pass an input signal between a source and a drain of a transistor, or to isolate the source from the drain, based on, for example, one or more control signals provided to a gate of the transistor.
Pass gates can pass various types of signals between an input and an output (e.g., the first and second terminals, respectively). The control signals for the one or more transistors in the pass gate can depend on the characteristics of the signal being transferred and the type of transistors in the pass gate. In certain examples, to keep the pass gate in a desired state, the control signals must be either more positive or more negative than the signals at the first or second terminals. In other examples, to provide an accurate representation of an input signal at an output, the control signals can follow the input signal, such as to provide a constant gate-to-source voltage of the one or more transistors, reducing impedance variation between the first and second terminals while the one or more transistors are in a desired state.